Deacon Bill was what is known as "a sound baseball man." He was an unexceptional player; his knowledge of the game exceeded his physical ability. In 1913 Yankee manager Frank Chance played him at second base despite his deficiencies because, he said, McKechnie "knew more baseball than all the rest of my team put together." McKechnie had a checkered career as a utility infielder. Between 1912 and 1916, he played for eight teams, including a one-game stint with the Braves. His two Federal League seasons (1914-15) were his most productive. Sold to the Giants when the Feds collapsed, he was included in the July 1916 trade that sent Hall of Famers Edd Roush and worn-out Christy Mathewson to the Reds for Buck Herzog and Wade Killefer.

Managing was his forte. He won pennants in three cities - a record that has never been matched. His first trial as a manager came at age 29, with the Newark Peps (FL) for 102 games in 1915. He succeeded George Gibson at Pittsburgh in mid-1922 and brought the club from fifth place to a tie for third. In 1925 he won his first pennant and defeated the Senators in the World Series, but was fired a year later when the appointment of former Pirate skipper Fred Clarke as a management consultant in the dugout led to confusion and a player revolt. After moving to St. Louis as a coach, McKechnie took the reins when Bob O'Farrell was removed for failing to win the 1927 pennant. McKechnie obliged Cardinal owner Sam Breadon by managing the Cardinals to first place in 1928, but the four-game World Series loss to the Yankees led to his 1929 demotion to Rochester (International League), while Rochester's manager, Billy Southworth, took over the Cardinals. Late in the season, Breadon decided he had made a mistake, and switched them back; combined, Southworth and McKechnie managed a fourth-place Cardinal finish.

McKechnie followed with eight years as the Braves' manager, never finishing higher than fourth. In 1935 Boston lost a club-record 115 games, but McKechnie remained through 1937. He spent nine seasons managing at Cincinnati, winning pennants in 1939 and 1940. In the 1939 WS he was swept by the Yankees again, but in 1940 his Reds beat the Tigers in seven.

A baseball conservative, Deacon Bill was more effective with pitchers than hitters, although his shrewd coaching of Larry Doby at Cleveland (1947-49) hastened the youngster's adjustment to the major leagues. He was strict with players, but his quiet self-discipline and fairness won their respect. McKechnie was money-conscious, and his moves to Boston and Cincinnati were for lucrative, long-term contracts. He was a churchgoer and family man, which earned him his nickname.